1. Field of the Invention
The invention relates to a device for stapling sheets which are individually supplied to, and stacked in a collection tray, in particular copy sheets produced by a copier whose collecting tray has a support surface that includes abutments for aligning sheets in an accurate position. The device comprises a stapling unit which is movable parallel with one of the abutments to a number of different stapling positions along a free space that is provided between an abutment and the support surface.
2. Description Relative to the Prior Art
A conventional device of this type comprises a collecting tray with a front abutment on which incoming sheets are aligned at their end sides and staples in sets. The stapling unit required for this purpose is movable along an abutment to various stapling positions, and the sheet support surface is provided with a free space through which the stapling device can pass freely. However, because sheets which during their transport through a copier are subjected to heat, pressure, static charge and the action of the transport mechanism tend to buckle more or less strongly, particularly in their marginal areas, a danger exists that such sheets may slip into the free space or slide across the front abutment.